Conventionally, as a means of rectifying an AC voltage VAC into a DC voltage VDC, a full-wave rectification circuit 100 using a diode bridge as shown in FIG. 19 is commonly used. Inconveniently, however, the diodes 101 to 104 constituting the diode bridge have a high forward voltage drop, which causes energy loss (power loss or heat generation in the diodes 101 to 104) during the periods in which current I passes through the diodes 101 to 104 (see the hatched areas in FIG. 20).
As an improvement, there has conventionally been proposed a switching rectifier circuit 200 in which, as shown in FIG. 21, diodes 101 to 104 as mentioned above are replaced with transistors 201 to 204, which are turned on and off with proper timing so as to convert an AC voltage VAC into a DC voltage VDC.
In this switching rectifier circuit 200, the timing with which the turning on and off of the transistor 201 is controlled is determined based on the comparison output from a comparator 206 (an output resulting from comparison between the DC voltage VDC and a first AC voltage VAC1); the timing with which the turning on and off of the transistor 202 is controlled is determined based on the comparison output from a comparator 207 (an output resulting from comparison between the DC voltage VDC and a second AC voltage VAC2). Moreover, the timing with which the turning on and off of the transistor 203 is controlled is determined based on the comparison output from a comparator 208 (an output resulting from comparison between the reference voltage VSS and the first AC voltage VAC1); the timing with which the turning on and off of the transistor 204 is controlled is determined based on the comparison output from a comparator 209 (an output resulting from comparison between the reference voltage VSS and the second AC voltage VAC1).
Examples of technologies related to what has been discussed above are found in Patent Documents 1 and 2 listed below.